Homopolymers of alkyl n-substituted maleimides



Patented Feb. 16, 1954 HOMOPOLYMERS F ABKYLrN-ZSUBSEIEI- TUTED MALEIMIDES John .J. 'Giammaria, to' Socony-Vacuum Woo'tlbury, N. il.,,assignor Oil Company,

Incorporated,

a corporation of New York No'Drawing. Application,

Serial No. '3 Claims. (01. 260-78) Thisxinvention relates to improved lubricating oil :compositions. More particularly, the: :inven- .tion is concerned with .mineral: llubricating oil compositions containing polymers of .N- alkyl lmaleilnides, in which the :alkyl tsubstituent s "a 4 normal, saturated, aliphatic :rad-ical .having from about 12 to about 18 carbon atoms, or a mixture of radicals, having from 8 to 18 carbon atoms, as pour depressants and viscosity index improvers.

,Itihas been showntin United States Patent .No. (2,301,356 that imides of olefinic dicarboxylic acids and certain N-substituted derivatives of "these imidesimay be copolymerized'with l-olefins, the polymer products havingcertain applications in-the field-of plastics. It is also known, :asrdisclosed in United States :that N-octadecyl maleimide can becopolymerized with styrene, the product being 'useful as-a imineral 'oil pour depressan Again, United: States Patent No. 2;e12;557 describes polymeric compounds derived by reaction of an alpha, beta ethylenic acid, or anhy- :dride,:and an unsaturated primary or secondary amine, in which :the lunsaturation .is :ethylenic and the ethylenic carbonatom nearest to the amino ;N- :atom is separatedifrom said ratom by at least foursingly-bondedzcarbon atoms. These polymers are claimed as. viscosity index improvers. Also, United States Patent No. '2;412-,708 describes similar polymeric products, except that the "alpha, beta, -.unsatura ted dicarboxyli'c acid, or anhydride, is reacted with both an unsaturat'ed'amine and a saturated, non-aromatic amine. Such polymers are claimed as ,pour point depressants as well as viscosity index improvers. In the latter two instances, polymerization occurs through both the 'maleic doublebond andtheisid'e chain double 'band'.

As distinguished from the ail-*0resai'd prior art disclosures, the present invention is directed to the preparation of N-alkyl *mal'eimidesobtained by" reacting substantally equimolar-quantities of m'a'leic anhydride and a primary, normal, saturated, aliphatic amine, followed by polymerizationof the maleimide'so produced to form products *useful'as pour depressantsand"viscosityindex improvers mineral oil's. It 'willi'be seen that polymerization of the N allgyl maleimid'es Patent-No.2,370,943,

September-29,1949, 118,104

contemplated herein, which correspond'to the general formula 'ZWI'IBIBiIl R is a primary, normal, saturated, aliphatic ,group, can take place only through the maleic .double bond and :thatthe polymer products obtained will, therefore, differ "from the products disclosed in Patents 2,412,557 and $412,708 discussed hereinabove.

'Itiis "the primary object of this invention to provide 'improvedmineral lubricating .oil compositions containing'polymers of "N-alkyl maleimides derived 'fromprimary, normaLjsaturated amines of from 12 to 18 carbon atoms, or mixturesiof'suchamines containing from "8 to 18 ,carbon atoms. Other objects 'will become apparent'irom What follows.

Since, 'asfaras is known, "the maleimide polymers contemplated 'herein have not been-known heretofore, they are claimed herein as-new compositions of matter.

aceordancew'ith this invention, the iN-alkyl maleimfdes are prepared by mixing equimdlar "quantitiesof maleic anhydride and "a primary, normal, saturated, aliphatic amine and heating the reaction mixture ata temperature of from about 150 C. to aboutZOU" C. until the theoretical, quantity :of water-us split :out. The xN-alkyl maleimide thus: formed is then polymerized by heating at :moderate itemperatures, :i'. e from about :C. toabout C. inithe :presence of a; small amount, i; "e. fromxahout 21 :per :cent :toabout figper icent:ofsanzorganic peroxide, suchas henzoylrgperoaide, forwa period 'of. time ranging from about 1. item up to about mo. hours.

As aforesaid, the primary, normal, saturated, aliphatic amines suitable for'use in the invention are those having from .8 to. 18\carbonlatoms. Specifical .octyl .a'mine, nonyl .amine, ,decyl amine, ..undecyl .amine, .do decyl amine, tridecyl amine, tetradecyl amine, pentadeoyl amine, hexadecyl amine, heptadecyl amine and .oc'tadecyl "amine .may be used. Mixtures .of these ammes lmay'also be used Amines-10f the, char- 3 acter useful in the invention Armour and Co. under the Armeen name. These include:

are marketed by trade Armeen CD (mixed C8 to C18 primary amines) Armeen 12D (n-dodecylamine) Armeen 14D (n-tetradecylamine) Armeen 16D (nhexadecylamine) and Armeen 18D (n-octadecylamine).

had from the following illustrative examples and results of tests.

EXAMPLE I Ninety-eight grams of maleic anhydride and 220 grams of Armeen CD, a mixture of primary, aliphatic amines containing 8 to 18 carbon atoms, were dissolved in 200 cc. of Sovasol 74, a highboiling petroleum solvent. The solution was heated at 175 C., the water of reaction being azeotropically distilled into a suitable side-arm trap. After 17 cc. of water were collected, a major the reaction mixture and the temperature raised to 180 C. The mixture was then cooled and poured into acetone. Precipitated material, presumably the diamide or unconverted monoamide, was removed by filtering. The acetone was evaporated from the filtrate and any remaining Sovasol 74 was distilled by heating to 210 C. under 150 mm. vacuum. The residue, representing the Armeen CD maleimide, was a brown, viscous oil.

Thirty grams of the above were mixed with 0.9 gram of benzoyl peroxide and heated slowly to 100 C. The source of heat was removed at this point but the temperature continued to rise to 121 C. As the temperature subsided heat was again applied t 100 C. and maintained for 48 hours. The viscous product was cooled, dissolved in benzene and washed with hot water. The solution was then filtered and the solvent distilled to obtain the finished polymerized maleimide as a dark viscous oil.

EXAlVIPLE II Forty-nine grams of maleic anhydride and 92.5 grams of Armeen 12D, a relatively pure ndodecylamine, were reacted as in Example I.

Twenty-six and one-half grams of the N- dodecyl maleimide from above and 0.79 gram of benzoyl peroxide were heated at 130 C. for 24 hours. The polymer, a dark brown, viscous oil, was purified as previously described.

EXAMPLE III Fifteen and two-tenths grams of maleic anhydride and 33.0 grams of Armeen 14D, a relatively pure n-tetradecylamine, were reacted as in Example I.

Ten grams of N-tetradecyl maleimide from above and 0.3 gram of benzoyl peroxide were heated at 100 C. for 16 hours. The polymer, a

portion of the solvent was distilled from dark brown, viscous oil, was purified as described in Example I.

EXAMPLE IV Forty-nine grams of maleic anhydride and 120.5 grams of Armeen 16D, a relatively pure nhexadecyl amine, were reacted as in Example I, except that the product was not poured into acetone.

Twenty grams of the N-hexadecyl maleimide from above and 0.6 gram of benzoyl peroxide were heated at C. for 24 hours. The polymer, a dark brown, waxy solid, was purified as before.

EXAMPLE V Sixty-nine grams of maleic anhydride and 188 grams of Armeen 18D, a relatively pure n-octadecylamine, were reacted as in Example I.

Twenty-five grams of N-octadecyl maleimide from above and 0.75 gram of benzoyl peroxide were heated at 100 C. for 92 hours. The polymer, a dark brown, waxy solid, was purified as previously described.

POUR POINT DEPRESSION The effectiveness of the various polymers as pour depressants in mineral lubricating oils is illustrated in Table I. The results were obtained using a Mid-Continent type base oil having a kinematic viscosity of 12.2 centistokes at 210 F.

These data illustrate the critical nature of the alkyl group in the substituted maleimide since only polymerized N-tetradecyl maleimide (Example III) and N-hexadecyl maleimide (Example IV) showed activity as pour depressants.

VISCOSITY INDEX IMPROVEMENT The effectiveness of the polymers as improvers of the viscosity index of mineral lubricating oil is illustrated in Table II. These results were obtained in an acid-refined Mid-Continent type oil stock having an initial viscosity index of 78.0.

Table II Kin. v15. Polymer Blended 8$, Viscosity in Oil Perce'nt Index 0 30.02 4.17 78.0 Example 11.. 2 31.82 5.01 86. 8 Example v- 31.76 5. 02 88.0

The polymeric materials of this invention may be incorporated in lubricating oils in concentrations ranging from 0.01% to 20%. Normally, a higher concentration will be required to effect a satisfactory improvement in viscosity index than will be required to effect a satisfactory lowering of the pour point of the oil. For the latter purpose, a concentration of 0.01% to 2% is preferred.

It is within the concept of this invention to incorporate the new polymeric materials in oils containing other improving agents such as antioxidants, detergents, extreme pressure lubrication improvers, stabilizing agents, rust inhibitors and the like. v

It is further contemplated that the products of this invention may be prepared and marketed in their pure form, that is, without admixture with lubricating oils, or may be prepared and marketed in concentrated solutions in oil, which concentrated solutions are adapted to be added to further quantities of oil to improve its characteristics.

Although the principles of the invention have been illustrated herein by means of certain examples and tests, it is not intended that the invention be in any way limited thereby, but only as indicated in the following claims.

I claim:

1. As a new composition of matter, a homopolymer of an N-alkyl maleimide selected from the group consisting of a homopolymer of N- tetradecyl maleimide and a homopolymer of N- hexadecyl maleimide.

2. As a new composition of matter, a homopolymer of N-tetradecyl maleimide.

3. As a new composition of matter, a homopolymer of N-hexadecyl maleimide.

JOHN J. GIAMMARIA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,301,356 Arnold et a1 Nov. 10, 1942 2,306,918 Weiss et al. Dec. 29, 1942 2,370,943 Dietrich Mar. 6, 1945 

1. AS A NEW COMPOSITION OF MATTER, A HOMOPOLYMER OF AN N-ALKYL MALEIMIDE SELECTED FROM THE GROUP CONSISTING OF A HOMOPOLYMER OF NTETRADECYL MALEIMIDE AND A HOMOPOLYMER OF NHEXADECYL MALEIMIDE. 